Prime Directive

In the Star Trek universe, a rule that
prohibits Starfleet personnel and spacecraft from interfering in the normal
development of any society. This means no Starfleet mission can involve
itself in a planet's internal conflicts or supply advanced technology to
it. Adopted relatively early in Starfleet history, the Prime Directive was
a key part of Starfleet and Federation policy toward newly discovered civilizations,
but it was also one of the most difficult to administer. In most cases,
the Prime Directive applied to any civilization that had not yet developed
the use of warp drive for interstellar
travel. This rule was not in force in 2168, when the U.S.S. Horizon
contacted planet Sigma Iotia II, resulting in disastrous cultural contamination.